1. Field of the Invention
The storage and transportation of particulate materials such as grains, sawdust, wood chips, feeds, similar powdery materials, and even such materials having a liquid component, has been a matter of industry concern for several years. Materials such as those identified above will be referred to hereinafter simply as particulate materials.
Hoppers, bins and silos are all capable of storage of such materials, but are of limited use in transportation. Moreover, costs incident to the construction of such vessels, which is labor intensive, approaches the prohibitive.
Walking floors, sometimes referred to as reciprocating conveyors, have been found useful in the loading and unloading of more readily available rectangular enclosures wherein difficulty is encountered in using front end loaders, or other similar devices, to accomplish the task of moving particulate material into and out of a storage or transportation facility.
Such systems typically comprise a series of floor members, sometimes referred to as slats, which are disposed in side by side relation to form a flat surface or floor. Each of the floor members is movable fore and aft, either in unison, or in opposition, to move material disposed on the floor in either a fore or aft direction.
Systems of the type to which this invention relates, exhibit several problems which have been the focus of industry wide research since the systems began to enjoy acceptance. A major problem is one of leakage of particulate material through the floor. Such leakage creates problems in two broad areas. First, the material that actually leaks of passes through the floor members may be lost forever to the owner, and the quantity, over a trip of several miles could be measured in tons. Secondly, if the particulate material is not lost entirely, it will most certainly accumulate beneath the floor, and in so doing, pack together, eventually raising the floor, or creating frictional loads of significant magnitude, such that efficient operation of the floor becomes gravely impaired.
Until the advent of the present invention, problems such as those identified continue to diminish the acceptance of walking floor systems, particularly in the transportation industry.
2. Overview of the Prior Art
The type of system for which the present invention has particular utility is illustrated generally in Wilkens U.S. Pat. No. 5,325,957 and Quaeck Pat. 5,222,593. Wilkens is also illustrative of the problem addressed by the present invention. Referring to FIG. 4, the bearing surfaces 90 and 92 are abutting, as illustrated. However, as these surfaces wear, particulate matter will filter down to the space, or pocket, defined between the integral walls 88 and will, if unable to escape, build up and become impacted against the horizontal floor slat retainer surface 80. Eventually the material will apply pressure to the surface 80, causing the slats to skew, increasing resistance to movement, and impairing the ability of the slats to move at all.
A myriad of solutions can be found in the patent art, such as, for example, in Hallstrom, Jr. U.S. Pat. No. 5,267,641, in which a system is disclosed for wiping away accumulated material beneath the slats. The disclosure makes no real pretense, however, of preventing the infiltration of such material in to the guide and bearing area beneath the slats.
Halstrom, Jr. was prolific in this area, however, and in a related U.S. Pat. No. 5,088,595, he employs essentially the same structure to effect a waterproof seal, which is accomplished by a "U" shaped flexible fluid impervious seal, 72, which caps abutting lateral extensions of the base members.
Foster, in his U.S. Pat. Nos. 4,896,761 and 4,858,748, both of which appear to have their beginnings in the same concept, employs a seal strip 38 between adjacent slats to prevent the incursion of particulate beneath the floor. Not unexpectedly, however, that seal wears and must be replaced, at a not insignificant cost.
Wilkens U.S. Pat. No. 5,301,798 discloses vertical bearing surfaces 84, which the inventor states, in column 5, acts as a seal in concert with an adjacent such surface. When wear is suffered by these surfaces, however, replacement rather than repair is the rule.
Quaeck also attempted to address the problem in U.S. Pat. Nos. 5,323,894 and 5,346,056, both or which sprang from the same application, by cutting a slot, or groove, in a side bearing 8. The groove receives flanges 82 formed on the edges of the slats, and, hopefully, prevents the incursion of particulate material beneath the floor. This system, while having some superficial appearance similar to that of the seals of the present invention, is entirely different in the scheme of things, as will appear from a further reading of this specification.